The Tigers found themselves in unfamiliar territory as they were hounded off the ball and limited to just five penalty goals, with Saints scoring two well-taken tries on the day.
Both Northampton tries were scored by former All Black wing Bruce Reihana – on either side of the break – and they helped the Saints into the driving-seat, although a 19-point haul from fly-half Shane Drahm that made all the difference.
Reihana's first try followed an exchange of penalties, and saw the wing come onto the ball from a short-range scrum to crash over the line.
Drahm added another six points before the first half trickled out to a series of ugly incidents, which saw Tigers hooker George Chuter and Saints prop Chris Budgen receive yellow cards.
Northampton used the elements in the second half and former England fullback Nick Beal slotted a massive drop-goal from 60 metres to sway the advantage firmly in the visitors' favour.
Ollie Smith kept the Tigers in the chase with a fine break, but the home side failed to cross the line at any stage of the contest.
By the time Reihana broke down the blindside to score his second five-pointer it was all over, with Tigers coach Dean Richards no doubt praying for the swift return of his England internationals.
For Leicester:Pens: Booth 5
For Northampton Saints:Tries: Reihana 2Con: DrahmPens: Drahm 5DG: Beal